<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        canvas {
            border: 1px solid #ccc;
        }
    </style>
</head>
<body>
<canvas width="600" height="400"></canvas>
<script>
    var myCanvas = document.querySelector('canvas');
    var ctx = myCanvas.getContext('2d');
	
	// 1.体验曲线的绘制
	// 2.线是由点构成的
	// 3.曲线可以由数学公式得来
	
	/*公式：y = x/2 */
	/*公式：y = (x + 2) ^2  */
	/*公式：y = sin(x) */
	
	for(var i = 1 ; i < 600 ; i++) {
		var x = i;
		//var y = x/2;
		//var y = Math.pow(x/10-30,2);
		var y = 50*Math.sin(x/10) + 100;
		ctx.lineTo(x,y);
	}
	ctx.stroke();
</script>
</body>
</html>